1. Field of the Invention
The present invention relates to a magnetic memory cell and a random access memory equipped with a high-output tunnel magnetoresistance device.
2. Description of the Related Art
Attempts have been made to apply a high-output tunnel magnetoresistance device to a recording/reading cell of a highly-integrated magnetic memory. Examples that have been disclosed as such tunnel magnetoresistance devices include, a tunnel magnetoresistance device with its insulator made of Al-oxide and a tunnel magnetoresistance device with an insulating film made of magnesium oxide (T. Miyazaki and N. Tezuka, J. Magn. Magn. Mater. 139, L231 (1995); and S. Yuasa. et al., Nature Material 3, 868(2004)). In a nonvolatile magnetic memory of conventional-type, the memory cell is made up by forming a tunnel magnetoresistance device on a MOSFET. The MOSFET is used for switching to pass a current through a bit line and a word line. A current-induced, spatial magnetic field thus generated is used to rotate the magnetization direction of the tunnel magnetoresistance device to store data, while recalling data is accomplished by the output voltage of the tunnel magnetoresistance device. Besides the above-mentioned magnetization-rotation method using current-induced spatial magnetic field, another method is disclosed, for example, in the specification of U.S. Pat. No. 5,695,864, and in Japanese Patent Application Laid-open No. 2002-305337. The disclosed method is known as a spin transfer torque magnetization reversal method, in which, rotation of magnetization is accomplished by passing a current directly through a magnetoresistance device. In addition, Japanese Patent Application Laid-open No. 2005-50907 discloses a way of applying a magnetic field, in which a magnetic field is applied in a direction parallel to the magnetic easy axis direction of the ferromagnetic free layer.